Obsolete TransZorb — what the ratings mean for fit
The 1.5KE33-E3/54: This is a single unidirectional channel in a through-hole DO-201AA (DO-27) axial package. The 47.7 V clamp means the protected rail sees no more than that voltage during a surge — critical for downstream 24 V or 28 V bus components that must survive transients without secondary breakdown.
Lifecycle reality — obsolete, no official successor
Vishay has marked the 1.5KE33-/54 as Obsolete. No replacement order code is recorded from the manufacturer. For a BOM that requires this exact clamp voltage and package, the only sourcing path is the spot market. Read the PCN before you buy — date-code provenance and lot traceability matter more here than on an active part.
Temperature range and package fit
The DO-201AA axial lead package mounts through-hole, which simplifies rework and prototyping but occupies more board area than a surface-mount equivalent.